The objectives of the proposed research are to study synaptic function in three aspects: (1) the turnover of proteins in the synaptic junctional membranes in discrete areas of brain; (2) the regulation of endorphin biosynthesis in brain; and the regulation of activity in some enzymes localized in synaptic membranes, adenylate cyclase and protein kinase. Each aspect will be examined in the brains of control animals and of animals treated acutely or chronically with opiates. The specificity of any opiate effects found in these experiments will be tested by the criteria of naloxone reversibility and stereospecificity. In earlier studies, we have separated junctional from non-junctional synaptic membranes and measured the levels and turnover rates of proteins separated by gel electrophoresis in these two membrane fractions and in those from synaptic vesicles. We intend to separate postsynaptic proteins from presynaptic proteins in preparations from discrete brain areas such as the caudate nucleus or the periaqueductal gray matter in order to examine the effect of opiates on the turnover of proteins in specific types of synapses. We have found that the administration of morphine to rats depresses the phophorylation of specific membrane proteins, and proposed to identify the proteins so affected. In preliminary studies, we have found that H3-glycine is incorporated into enkephalins in vivo within 30 to 120 minutes of injecting the labeled amino acid. We propose to separate the endorphins by HPLC and immuno assay in order to examine the turnover of the individual endorphins in brain, as affected by opiates.